Which substance is known to interfere with creatinine measurement by the Jaffe reaction, causing an apparent increase?

Which substance is known to interfere with creatinine measurement by the Jaffe reaction, causing an apparent increase?

• A. Ascorbic acid
• B. Bilirubin
• C. Glucose
• D. α-Keto acids

Answer: (B)

The Jaffe reaction is a colorimetric method that measures creatinine by forming a colored complex with picrate in basic solution. Because the measurement relies on color intensity at a specific wavelength, any substance in the sample that contributes color at that wavelength can skew the result. Bilirubin is a yellow pigment that colors the sample itself. When bilirubin is present, its color adds to the overall absorbance of the sample, making the detected signal appear larger than it should be from creatinine alone. This effect yields an apparent increase in measured creatinine, a classic example of positive interference in the Jaffe method. In jaundiced samples or those with high bilirubin, this can lead to falsely elevated creatinine values. Other substances like ascorbic acid, glucose, or α-keto acids can interfere in some contexts, but bilirubin is the most well-known cause of an apparent increase in this particular assay.

The Jaffe reaction is a colorimetric method that measures creatinine by forming a colored complex with picrate in basic solution. Because the measurement relies on color intensity at a specific wavelength, any substance in the sample that contributes color at that wavelength can skew the result.

Bilirubin is a yellow pigment that colors the sample itself. When bilirubin is present, its color adds to the overall absorbance of the sample, making the detected signal appear larger than it should be from creatinine alone. This effect yields an apparent increase in measured creatinine, a classic example of positive interference in the Jaffe method. In jaundiced samples or those with high bilirubin, this can lead to falsely elevated creatinine values.

Other substances like ascorbic acid, glucose, or α-keto acids can interfere in some contexts, but bilirubin is the most well-known cause of an apparent increase in this particular assay.